Natural gas is generally a hydrocarbon gas mixture consisting primarily of methane, and includes varying amounts of other alkanes, carbon dioxide, nitrogen, hydrogen sulfide, and other rare gases. Accordingly, natural gas for commercial and industrial use comes in a wide array of compositions. Natural gas is an energy source and used in varied applications. For example, natural gas is used for heating, cooking, power generation, transportation, and has many other utilities. Additionally, natural gas is used as fuel for vehicles and as a chemical feedstock in the manufacture of plastics and other commercially important organic chemicals. Due to the wide array of compositions of the natural gas and broad applications, analysis of natural gas is required.
Conventionally, natural gas is analyzed using gas chromatographs. However, gas chromatographs tend to be bulky, slow, and require frequent calibrations. Other conventional techniques entail absorption based optical techniques, such as photo acoustic spectroscopy, tunable diode laser spectroscopy, or broadband absorption spectroscopy. Generally, the absorption based optical techniques are imprecise due to spectral interference from different natural gas components. Additionally, the absorption based optical techniques are imprecise due to various inert gases that do not have absorption lines, and therefore such inert gases cannot be detected using the absorption based optical techniques. For example, gases, such as, H2 and N2 cannot be measured using absorption based optical techniques.
Another conventional optical analysis technique that may be used for analysis of natural gas is Raman spectroscopy or Raman scattering. Raman scattering entails irradiation of the atoms and molecules of natural gas by photons (hereinafter referred to as ‘incident photons’) of a light beam. The irradiation of the atoms and molecules of the natural gas, by the incident photons, in-elastically scatters a very small fraction of the incident photons. The in-elastically scattered incident photons constitute Raman signals. The Raman signals may thus be used for the analysis of the natural gas. However, due to the small fraction of the in-elastically scattered photons, the signal to noise ratio of the Raman signals is very low which may result in imprecise analysis of the natural gas.
Therefore, it would be advantageous to provide improved systems and methods to analyze natural gas with improved precision and speed. Furthermore, it would be desirable to provide novel and compact systems for analyzing natural gas.